textproduct: Rapid City

KEY MESSAGES

- Thursday still looks to be cool.

- Anticipated rainfall through the overnight/Thursday now beginning to look more spotty.

- Hot and dry conditions through the weekend and into the first of next week still look likely.

DISCUSSION

(This Evening Through Wednesday) Issued at 116 PM MDT Wed Jul 22 2026

Latest water vapor imagery shows center of upper high pressure located across nrn TX/OK with ridge axis pointed northeast into Pacific NW. Monsoonal moisture continues to stream around the periphery of the ridge. Minor waves are located across eastern ID/southwest MT/western WY with another lifting northward through UT. At the surface, high pressure located across the eastern Dakotas with a weak lee trough located along the Big Horns. Temperatures at 18Z across the CWA range from the 60s in the cloud covered areas across the east, to the mid 70s to lower 80s in the partly cloudy areas.

The biggest issue facing the near-term forecast will be the expected rainfall overnight into Thursday. Models have backed off on strength/timing and track of the wave now moving through MT/WY. Deterministic models now have this feature sliding just a bit further south than previous runs, taking expected rainfall also a bit further south. Expected pwats are still high, running 150-200% of normal overnight through Thursday. Ensembles show probability of 1.75"+ pwats increasing to 60-90% during the day Thursday across our southern counties. However, ensembles also show probabilities of receiving 0.25" or higher pcpn only on the order of 30-40%, and again mainly relegated to areas mainly south of I-90. Things remain pretty transitory so not too worried about any flooding/flash flooding issues. Still wouldn't be surprised to hear of some localized 1"+ rainfall amounts by the close of day Thursday, but thinking now it won't be as widespread as earlier thought.

After that, hot and dry will be the rule heading into next week. With a more spotty nature to the rainfall, there may not be as much moisture to burn off on Friday than previously thought. Deterministic models have actually trended higher for forecasted highs on Friday. With 700hpa temps pushing +20C and 850hpa temps +36C by 00Z Sunday, not concerned about any convection developing over the Black Hills. Will most likely need heat headlines (again) for the upcoming weekend.

AVIATION

(For the 06Z TAFS Through 06Z Thursday Night) Issued At 955 PM MDT Wed Jul 22 2026

Light showers have moved into northeastern WY and will spread into western SD. SHRA is expected to continue through the night and potentially through Thursday afternoon, particularly in SD. Conditions will largely be VFR, but MFVR/IFR conditions may be possible near stronger precipitation.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.